<?php
/*
 *  $Id: Unique.php 3884 2008-02-22 18:26:35Z jwage $
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This software consists of voluntary contributions made by many individuals
 * and is licensed under the LGPL. For more information, see
 * <http://www.phpdoctrine.org>.
 */

/**
 * ActiveRecord_Validator_Unique
 *
 * @package     ActiveRecord
 * @subpackage  Validator
 * @link        www.phpdoctrine.org
 * @author      Konsta Vesterinen <kvesteri@cc.hut.fi>
 * @author      Richard Standbrook <richard@koorb.co.uk>
 */
class ActiveRecord_Validator_Unique implements ActiveRecord_Validator_Interface
{
    /**
     * checks if given value is unique
     *
     * @param mixed $value
     * @return boolean
     */
    public function validate($value, $field, ActiveRecord $invoker)
    {
        $tableName = $invoker->getTableName();
        $values = array();
        $values[] = $value;

        $sql = 'SELECT id FROM ' . $tableName . ' WHERE ' . $field . ' = ?';
        
        // If the record is not new we need to add primary key checks because its ok if the 
        // unique value already exists in the database IF the record in the database is the same
        // as the one that is validated here.
        $state = $invoker->state();
        if ( ! ($state == ActiveRecord::STATE_DIRTY || $state == ActiveRecord::STATE_CLEAN)) {
            $sql .= " AND id != ?";
            $values[] = $invoker->id;
        }
        
        $q = $invoker->db->query($sql, $values);

        return ( $query->num_rows() > 0);
    }
}